Clothing and textile materials are not only carriers of microorganisms such as pathogenic bacteria, odor generating bacteria and mould fungi, but also good media for the growth of microorganisms. The inherent properties of the textile fibers provide room for the growth of micro-organisms. Humid and warm environment still aggravate the problem. Infestation by microbes cause cross infection by pathogens and development odor where the fabric is worn next to the skin. In addition, the staining and loss of the performance properties of textile substrates are the results of microbial attack. Obnoxious smell from the inner garments such as socks, spread of diseases, staining and degradation of textiles are some of the detrimental effects of bad microbes.
Though the use of antimicrobials have been known for the decades, it is only in the recent couple of years several attempts have been made on finishing textiles with antimicrobial compounds. Antimicrobial finish is a recent innovation in finishes. It also prevents garments from unpleasant odor.
The most common technology for making durable Antimicrobial apparel fabric is to introduce silver ion at the polymerization stage of the fibre manufacturing or to treat the fabric with nano-silver ions during finishing. But silver ion has many adverse effects on human being as well as on environment such as:
i) When human skin cells grown in a Petri-dish were exposed to nano-silver particles 7-20 nm in size, concentration dependent changes to cell morphology including abnormal size, shrinkage and rounded appearance were observed at concentrations above 6.25 microgm/ml.
ii) Nano silver has also some adverse effect on wound. After a week of treatment with a wound dressing impregnated with nano silver, the patient developed reversible sign of liver toxicity and a grayish dis-colouration of his face similar to that found in patient diagnosed with argyria.found. When wound dressing was removed, the clinical symptoms returned to normal in ten months.
iii) Nanosilver has recently been found at concentration as low as 0.14 micro gm/ml to be toxic to several species of nitrifying bacteria, which play an important role in the environment by converting ammonia in the soil to a form of nitrogen that can be used by plants. Increase in mass usage of Silver treated AMB fabric and the effluent generated during home laundering of garments may contaminate soil/water.
iv) Nanosilver's primary use as an antimicrobial has attracted the attention of the US Environment protection Agency which enforces the federal insecticides, Fungicide and Rodenticide Act (FIFRA). Also in Europe, the key question is whether nano-silver will be considered a new substance and therefore subjected to the rigorous notification procedure required under REACH law.
Nanosilver cannot be filtered out fully in Effluent Treatment Plant (ETP) and likely to cause soil and water contamination. Also the presence of Silver ion in the effluent water increases the load on Effluent treatment plant substantially. Nano-silver ion based AMB technology has been known to require several precautions in application as well as many costly modifications in effluent water treatment process.    (Ref:—Environmental Impact of Nanosilver—by Kristen M. Kulinowski, Ph. D—Nov. 18, -2008)
Apart from silver, antiseptics and disinfectants are extensively used in hospitals and other health care settings for a variety of topical and hard-surface applications. A wide variety of active chemical agents (biocides) are found in these products, many of which have been used for hundreds of years, including alcohols, phenols, iodine, and chlorine. Most of these active agents demonstrate broad-spectrum antimicrobial activity.
Chlorine- and iodine-based compounds are the most significant microbicidal halogens used in the clinic and have been traditionally used for both antiseptic and disinfectant purposes.
Chloro compounds such as Chloroxylenol is an effective antimicrobial agent. It is used as bacteriocidal, fungicidal and germicidal agent.
Many antimicrobial agents used in the textile industry are known from the food stuff and cosmetics sector. These substances are incorporated with textile substrates comparatively at lower concentrations. It must be ensured that these substances are not only permanently effective but also that they are compatible with skin and the environment.
Other chemical used for producing durable antimicrobial (AMB) fabric is 3-trimethoxy silyl propyl dimethyl octadecyl ammonium chloride—but it has also some disadvantages                yellowing of the shade/colour of the fabric.        it is a cationic compound—If any anionic detergent is used during home laundering, it will take out the cationic compound from the fabric making the anti-microbial effect less durable.        
Following patents disclose anti-microbial fabrics and processes for preparing the same.
U.S. Pat. No. 3,699,958 disclose an antimicrobial woven or knitted fabric, characterized in that it is made using crimp yarn and is treated with cation-active antimicrobial compounds such as benzalkyl ammonium derivates, phenolic polyoxymethylene derivates.
U.S. Pat. No. 6,368,361 discloses a process for manufacturing an antibacterial fiber, characterized in that fiber is contacted with or immersed in an aqueous solution in which a cationic surfactant with a quaternary ammonium salt group, a water-soluble protein, and an alkaline compound are dissolved; and the fiber is separated from the aqueous solution and immersed in another aqueous solution containing tea polyphenol.
U.S. Pat. No. 6,780,799 discloses an antimicrobial non-woven fabric comprising: a polymeric fiber substrate comprising phosphonic acid groups covalently bonded thereto and antimicrobial agents ionically bonded to the phosphonic acid groups. The antimicrobial agent used is benzalkonium chloride.
U.S. Pat. No. 6,821,936 discloses a wash durable antimicrobial treated substrate comprising an antimicrobial silver finish comprising silver zirconium phosphate compounds; at least one binder material selected from the group consisting of nonionic materials, anionic materials, and any mixtures thereof; and a substrate selected from the group consisting of a yarn, a fabric comprised of individual fibers, and a film;
U.S. Pat. No. 6,946,433 discloses a process for producing a wash durable antimicrobial treated substrate comprising an antimicrobial silver finish comprising compounds selected from the group consisting of silver-containing ion exchange compounds, silver-containing zeolites, silver-containing glass, and any mixtures thereof; and a substrate selected from the group consisting of a yarn, a fabric comprised of individual fibers, and a film.
U.S. Pat. No. 7,081,139 discloses antimicrobial polyester-containing articles (filament, fiber, yarn, fabric or film) and methodology for the preparation of antimicrobial polyester-containing articles utilizing chitosan and chitosan-metal complexes as the antimicrobial agent.
U.S. Pat. No. 7,232,777 discloses yarns and fabrics having a wash-durable antimicrobial silver particulate finish. It particularly disclose a treated substrate comprising a finish comprising a) solid compounds selected from the group consisting of metal particles, metal salts, metal oxides, and any combinations thereof, and b) at least one binder material selected from the group consisting of melamine-formaldehyde resins, acrylic resins, polyvinyl chloride/vinyl copolymers, and mixtures thereof: a substrate selected from the group consisting of a yarn, a fabric comprised of individual fibers, and a film.
U.S. Pat. No. 6146651 discloses a non-woven fabric treated with a biocidal composition, comprising: at least one halogenated phenolic biocide selected from the group consisting of pentachlorophenol (PCP), p-chloro-m-xylenol (PCMX), hexachlorophene, o-phenylphenol, dichlorophene, chlorophene, bromophene, trilosan and a combination thereof. ; a water soluble film forming polymer (polyvinylpyrrolidone polymer); and at least one surfactant.
The textile or fabrics containing antimicrobial agent disclosed in the above prior art does not provide effective and long lasting anti-microbial activity.
Thus, there is felt a need to develop antimicrobial finish on fabrics which is durable, completely safe for human being as well as for environment and does not alter the tone, colour and appearance of the fabric.